Better UML diagrams: Extending the Sugiyama Algorithm for Drawing UML Class Diagrams

Summary of the Document:

Paper by Jochen Seemann

In this paper he presents a technique for the automatic layout of UML class diagrams.
The algorithm consists of four stages:

Preparation : Remove direct cycles from the given graph and compute the subgraph that contains only classes with inheritance relations. The subgraph is a directed acyclic graph.
Sugiyama Layout: Compute a first layering for the subgraph according to nodes inheritance relationships. Reduce the number of crossing by using barycentric ordering.
Incremental Extension: Extend the layout incrementally, until all nodes have been placed in the diagram. Optimize the position of nodes in each layer to reduce the number of line crossings which also improves the aspect ratio of the diagram.
Orthogonal Drawing of Association Connection Edges: Sweep line algorithm is used when computing line segment positions of association relationships between classes on the same or adjacent layer.

Figure- Optimization using sublayers